sparc64: interrupt trap handling

cpu_check_irqs
- handle SOFTINT register TICK and STICK timer bits
- only check interrupt levels greater than PIL value
- handle preemption by higher level traps

cpu_exec
- handle CPU_INTERRUPT_HARD only if interrupts are enabled
- PIL 15 is not special level on sparcv9

Signed-off-by: Igor V. Kovalenko <igor.v.kovalenko@gmail.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>

3 files changed, 59 insertions, 27 deletions

diff --git a/cpu-exec.c b/cpu-exec.c
index af4595b..4635be3 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -449,20 +449,20 @@ int cpu_exec(CPUState *env1)
                         next_tb = 0;
                     }
 #elif defined(TARGET_SPARC)
-                    if ((interrupt_request & CPU_INTERRUPT_HARD) &&
-			cpu_interrupts_enabled(env)) {
-			int pil = env->interrupt_index & 15;
-			int type = env->interrupt_index & 0xf0;
-
-			if (((type == TT_EXTINT) &&
-			     (pil == 15 || pil > env->psrpil)) ||
-			    type != TT_EXTINT) {
-			    env->interrupt_request &= ~CPU_INTERRUPT_HARD;
-                            env->exception_index = env->interrupt_index;
-                            do_interrupt(env);
-			    env->interrupt_index = 0;
-                        next_tb = 0;
-			}
+                    if (interrupt_request & CPU_INTERRUPT_HARD) {
+                        if (cpu_interrupts_enabled(env) &&
+                            env->interrupt_index > 0) {
+                            int pil = env->interrupt_index & 0xf;
+                            int type = env->interrupt_index & 0xf0;
+
+                            if (((type == TT_EXTINT) &&
+                                  cpu_pil_allowed(env, pil)) ||
+                                  type != TT_EXTINT) {
+                                env->exception_index = env->interrupt_index;
+                                do_interrupt(env);
+                                next_tb = 0;
+                            }
+                        }
 		    } else if (interrupt_request & CPU_INTERRUPT_TIMER) {
 			//do_interrupt(0, 0, 0, 0, 0);
 			env->interrupt_request &= ~CPU_INTERRUPT_TIMER;
diff --git a/hw/sun4u.c b/hw/sun4u.c
index 029e3ed..ae32878 100644
--- a/hw/sun4u.c
+++ b/hw/sun4u.c
@@ -232,29 +232,51 @@ void irq_info(Monitor *mon)
 
 void cpu_check_irqs(CPUState *env)
 {
-    uint32_t pil = env->pil_in | (env->softint & ~SOFTINT_TIMER) |
-        ((env->softint & SOFTINT_TIMER) << 14);
+    uint32_t pil = env->pil_in |
+                  (env->softint & ~(SOFTINT_TIMER | SOFTINT_STIMER));
+
+    /* check if TM or SM in SOFTINT are set
+       setting these also causes interrupt 14 */
+    if (env->softint & (SOFTINT_TIMER | SOFTINT_STIMER)) {
+        pil |= 1 << 14;
+    }
+
+    if (!pil) {
+        if (env->interrupt_request & CPU_INTERRUPT_HARD) {
+            CPUIRQ_DPRINTF("Reset CPU IRQ (current interrupt %x)\n",
+                           env->interrupt_index);
+            env->interrupt_index = 0;
+            cpu_reset_interrupt(env, CPU_INTERRUPT_HARD);
+        }
+        return;
+    }
+
+    if (cpu_interrupts_enabled(env)) {
 
-    if (pil && (env->interrupt_index == 0 ||
-                (env->interrupt_index & ~15) == TT_EXTINT)) {
         unsigned int i;
 
-        for (i = 15; i > 0; i--) {
+        for (i = 15; i > env->psrpil; i--) {
             if (pil & (1 << i)) {
                 int old_interrupt = env->interrupt_index;
-
-                env->interrupt_index = TT_EXTINT | i;
-                if (old_interrupt != env->interrupt_index) {
-                    CPUIRQ_DPRINTF("Set CPU IRQ %d\n", i);
+                int new_interrupt = TT_EXTINT | i;
+
+                if (env->tl > 0 && cpu_tsptr(env)->tt > new_interrupt) {
+                    CPUIRQ_DPRINTF("Not setting CPU IRQ: TL=%d "
+                                   "current %x >= pending %x\n",
+                                   env->tl, cpu_tsptr(env)->tt, new_interrupt);
+                } else if (old_interrupt != new_interrupt) {
+                    env->interrupt_index = new_interrupt;
+                    CPUIRQ_DPRINTF("Set CPU IRQ %d old=%x new=%x\n", i,
+                                   old_interrupt, new_interrupt);
                     cpu_interrupt(env, CPU_INTERRUPT_HARD);
                 }
                 break;
             }
         }
-    } else if (!pil && (env->interrupt_index & ~15) == TT_EXTINT) {
-        CPUIRQ_DPRINTF("Reset CPU IRQ %d\n", env->interrupt_index & 15);
-        env->interrupt_index = 0;
-        cpu_reset_interrupt(env, CPU_INTERRUPT_HARD);
+    } else {
+        CPUIRQ_DPRINTF("Interrupts disabled, pil=%08x pil_in=%08x softint=%08x "
+                       "current interrupt %x\n",
+                       pil, env->pil_in, env->softint, env->interrupt_index);
     }
 }
 
diff --git a/target-sparc/cpu.h b/target-sparc/cpu.h
index e5b282d..50859c7 100644
--- a/target-sparc/cpu.h
+++ b/target-sparc/cpu.h
@@ -577,6 +577,16 @@ static inline int cpu_interrupts_enabled(CPUState *env1)
     return 0;
 }
 
+static inline int cpu_pil_allowed(CPUState *env1, int pil)
+{
+#if !defined(TARGET_SPARC64)
+    /* level 15 is non-maskable on sparc v8 */
+    return pil == 15 || pil > env1->psrpil;
+#else
+    return pil > env1->psrpil;
+#endif
+}
+
 static inline int cpu_fpu_enabled(CPUState *env1)
 {
 #if defined(CONFIG_USER_ONLY)